Blue vat dye.



UNITED STATES PATENT OFFICE.

MAX B Frfor VOI-IWINKEL,

FABRIKEN VORM. 'FRIEDR. TION or GERMANY.

NEAR ELBERFELD, GERMANY, ASSIGNOR TO FARBEN- BAYER & 00., OF ELBERFELD,GERMANY, A CORPORA- BLUE VAT DYE.

No Drawing.

' ized dark powders yielding with caustic 'in 150 parts of.nitrobenzene.

soda lye and ton fast blue.

The process probably proceeds ance with the following equationhydro-sulfite vats dyeing cotin accordoo (R meaning a hydrocarbonradical).

In order to illustrate the new process more fully the following. exampleis given, the parts being by weight-31.6 parts of lmethylamino 4bromoanthraquinone are suspended together with 14.7 parts of isatin Thisn1ixture is then heated to boiling While being s irred for 10 hours withthe addition of 20 parts of sodium acetate and 5 parts of cuprouschlorid. After the solution has cooled the crystalline condensationproduct is removed by .filtration and washed with alcohol and water. Itis a dark blue powder which is rather diflicultly soluble in mostorganic solvents. Concentrated sulfuric I Specification of LettersPatent. Application filed April 11, 1911.

Patented July 18, 1911. Serial No. 620,425. 0

acid dissolves it with a brown color. lVith hydro-sulfite and NaOH thenew product yields a brown vat from which cotton is dyed a greenish-blueshade, fast to light.

claims- 1. The herein described new dyestuffs having probably thefollowing general formula:

NHR

co I R meaning a hydrocarbon radical, which are after being dried andpulverized dark powders yielding vats with caustic soda lye andhydrosulfite which dye cotton blue fast shades, substantially asdescribed.

2. The herein described new dyestuif having probably the formula:

NELCHa witnesses.

MAXBUFF. [L. s.]

Witnesses v ALFRED HENKEL, N. SIRCKE.

